<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- <div class="a">
        aaa
    </div>

    <div class="a">
        bbb
    </div>

    <div class="a">
        ccc
    </div> -->
    
    <div>111</div>

    <!-- 内边距 -->
    <!-- <style>
        div{
            border: 1px solid black;
            padding: 25px 50px 50px 25px;
            padding-top: 25px;
            padding-bottom: 50px;
            padding-left: 25px;
            padding-right: 50px;
            
            
            background-color: lightblue;
        }
    </style> -->

    <style>
        /* 外边距 */
        div{
            width: 80px;
            height: 50px;
            color: white;
            background-color: #0000df;
            text-align: center;

            margin-top: 10px;
            margin-right: 10px;
            margin-bottom: 20px;
            margin-left: 20px;
            
            margin: 10px 10px 20px 20px;
        }
        
    </style>

    <!-- 块级元素水平居中 -->
    <style>
        div{
            width: 100px;
            height: 200px;
            background-color: blue;
            
            margin: 0 auto;
            margin: auto;
            margin-left: auto;
            margin-right: auto;
        }
        
        
    </style>

    <!-- 清除浏览器的默认样式 -->
    <!-- <style>
        div{
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
    </style> -->


    <!-- 弹性布局 -->
    <!-- <div>
        <span>111</span>
        <span>222</span>
        <span>333</span>
    </div> -->
    
    <!-- <div class="parent">
        <div class="child">111</div>
        <div class="child">222</div>
        <div class="child">333</div>
    </div> -->

    <!-- 主轴方向 -->
    <!-- <style>
        .parent{
            width:50%;
            height: 150px;
            background-color: red;
            display: flex;
            justify-content: flex-end;
            justify-content: center;
            justify-content: space-around;
            justify-content: space-between;
            
        }

        .child{
            width: 100px;
            height: 100px;
            background-color: #0000cf;
        }

    </style> -->

    <!-- 侧轴方向 -->
    <style>
        .parent{
            width: 100%;
            height: 200px;
            background-color: #990099;
            display: flex;
            justify-content: space-around;
            align-items: center;
            align-items: flex-start;
            align-items: flex-end;
            align-items: space-between;
            align-items: space-around;
        }

        .child{
            width: 50px;
            height: 20px;
            background-color: white;
        }
        
    </style>

</body>
</html>